Members of this family are usually annotated as putative carboxymuconolactone decarboxylases, are related also to alkylhydroperoxidase AhpD, and contain a peroxidase-like Cys-X-X-Cys putative redox-active disulfide. All members occur in genomes with a radical SAM protein of family TIGR04167, which occasionally are selenoproteins.